1. Field of the Invention
This invention relates to a medical guide wire which is to be penetrated into a somatic body to guide a catheter prior to inserting the catheter.
2. Description of Related Art
Upon inserting the catheter to a body so as to inject a contrast medium into an affected part, a metallic guide wire is used which extends by approx. 20 mm from a leading end of the catheter. After reaching the affected area, the guide wire is withdrawn with the catheter remaining at the affected area, and then the contrast medium is injected through the catheter into the affected area.
As this type of guide wire, there is provided a wire device disclosed by Japanese Patent Publication No. 4-20453. In the reference of Japanese Patent Publication No. 4-20453, a core wire is made by a plurality of thin threads, and a leading end of the core wire is constricted to form a thinned tip. On an entire surface of the core wire, a resin layer is coated. Both ends of the guide wire are crooked to flexibly move so that the guide wire can be smoothly inserted into a complicated and entangled vascular system.
However, it is feared that the thinned end of the twisted threads will become loose when treating the body with the thinned end, when the twisted threads are coated with a resin layer on the outer surface of the core wire. With the frequent use of the guide wire, the leading end of the thin threads tends to become unraveled so that the thin threads break the resin layer to expose the thin threads outside the resin layer so as to do harm on the somatic tissue system. This restricts the flexing turns and degree of the leading end of the guide wire. Moreover, the crooked end of the guide wire tends to be unidirectionally oriented so as to deteriorate its maneuverability.
Therefore, it is an object of the invention to provide a guide wire which is capable of effectively preventing the twisted end from inadvertenly becoming loose.
It is another object of the invention to provide a guide wire which is capable of improving a manipulability when encountering a bifurcating point of a vascular system.
It is yet another object of the invention to provide a method of efficiently making a guide wire.